A redox flow battery system includes an anolyte having chromium ions in solution, wherein at least a portion of the chromium ions form a chromium complex with at least one of the following: NH.sub.3, NH.sub.4.sup.+, CO(NH.sub.2).sub.2, SCN.sup.−, or CS(NH.sub.2).sub.2; a catholyte having iron ions in solution; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; and a first separator separating the first half-cell from the second half-cell.

The present invention provides a separator formed by hydrolysis of a resin film. The resin film comprises a non-hydrolyzable organic polymer; and a hydrolyzable organic polymer being hydrolyzable by treatment with at least one of an acid aqueous solution, an alkaline aqueous solution and pure water, wherein the content of the hydrolyzable organic polymer ranges from 10 parts by weight to 70 parts by weight relative to 100 parts by weight of the resin film. The separator of the present invention has good ion conductivity and thus, is extremely suitable for use in various types of batteries.

A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

The present disclosure discloses a flow battery system and a large-scale flow battery energy storage device. The flow battery system comprises multiple flow batteries; each of the flow batteries comprises a battery pack A, a battery pack B, a battery pack C, and a set of electrolyte circulation system used by the battery pack A, the battery pack B and the battery pack C; the battery pack A, the battery pack B and the battery pack C comprised in each flow battery are independent of each other in the circuit. According to the present disclosure, at least two sets of electrolyte circulation system are saved under the same power scale, such that the system stability is improved while the cost is reduced.

A flow-through redox galvanic cell and a battery is described, where each flow-through galvanic cell is separated into two parts by a metal foil serving as a bi-electrode in contact with two solutions having different redox potentials. Voltage due to redox processes is formed through the foil, and two traditional electrodes (cathode and anode) in each cell are not necessary anymore. The cells in a battery should be in electric contact with each other via ion-selective membranes. The battery is easy to recharge, and it is smaller, lighter, safer and cheaper than known redox-flow batteries. It may be used as a reserve source of energy in electric grids and households. It also may be used in electric cars, and it is especially attractive for use near the seashore and on sea ships.

A flow battery includes an electrochemical cell that has a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode. The separator layer is formed of a polymer that has a polymer backbone with cyclic groups that are free of unsaturated nitrogen and one or more polar groups bonded between the cyclic groups.

The present disclosure provides an electrohydraulic device. The device includes a battery having a vessel containing a flowable electrolyte. The battery may be a flow cell battery, such as, for example, a redox flow cell battery. In a flow cell battery, the flowable electrolyte may a catholyte and/or an anolyte. An actuator is in fluidic communication with the vessel of the battery. The actuator is configured to be actuated using the flowable electrolyte. A cation exchange membrane may separate the vessel into an anolyte side and a catholyte side. The actuator may be in fluidic communication with either side (anolyte side or catholyte side) of the vessel.

The present invention relates to new anion exchange polymers and (blend) membranes made from polymers containing highly fluorinated aromatic groups by means of nucleophilic substitution and processes for their production by means of nucleophilic aromatic substitution and their areas of application in membrane processes, in particular in electrochemical membrane processes such as fuel cells, electrolysis and redox flow batteries.

Systems and methods are provided for a rebalancing cell for a redox flow battery. In one example, a rebalancing cell for a redox flow battery includes a cell enclosure and a stack of electrode assemblies enclosed by the cell enclosure, where each electrode assembly of the stack of electrode assemblies including a positive electrode interfacing with a flow field plate. A face of the flow field plate interfacing with the positive electrode has a plurality of passages including tapered inlets and outlets and partial channels configured to remove gas from electrolyte flowing therethrough.

The invention provides flow batteries including an anthraquinone and methods of discharging the batteries that reduce loss of capacity. The loss of capacity of anthraquinones may be mitigated by controlling the state of charge and/or oxidizing the negolyte.